(1) Field of the Invention
The invention generally relates to breast pumps and specifically to manually operable breast pumps of the type having a suction pump and being suitable for actuation with one hand only.
(2) Description of the Prior Art
Breast pumps for manual operation of the type disclosed, for example, in Applicants' U.S. Pat. No. 4,573,969 (EP 116,186) will normally be held in one hand, generally around the suction bell and near the breast while the other hand actuates motion of that pump component that causes suction.
Various improvements of such pumps have been introduced since, e.g. use of a small battery-operated motor as disclosed in Applicants' U.S. Pat. No. 4,673,388, or soft inserts into the suction bell as disclosed in U.S. Pat. No. 4,799,922.
Many prior art manual breast pumps of the general type disclosed in U.S. Pat. No. 3,822,703 can be operated "single-handed" in the sense that the breast pump is held and operated with one hand only and this may be advantageous because the mother will then be able to stimulate or press the breast so as to improve lactation and completeness of the milk discharge. Single-handed breast pumps have suffered from one or more disadvantages including poor visual control of operation (including actual milk discharge and lactation of the breast) and maintenance (i.e. cleaning or control of cleaning effectiveness). For example, a single-handed breast pump suggested more recently (e.g. in published British Pat. Application No. 2,166,353-A), while avoiding some disadvantages of previous single-handed breast pumps by replacing the conventional rubber ball with a pump arrangement, fails to provide a satisfactory solution. This prior art pump comprises a milk reservoir and a closure member for connection therewith; the closure member comprises a suction bell and a suction pump which, in turn, includes a cylinder integrally connected with the closure member, a piston for reciprocating motion within the cylinder and an actuator formed of a handle and a steel spring that is loaded (i.e. accumulates energy) when the handle is pressed downwards causing suction by lifting the piston within the cylinder; upon release of the handle the steel spring causes the handle to revert into its rest position and brings the piston back into its lowermost position within the cylinder. However, the use of metal components is not favored for breast pumps and the structure of the prior art actuator precludes sufficient visual control. Further, pumping by means of the handle involves an essentially asymmetrical motion which may cause the suction bell to be displaced more than is felt by the mother to be comfortable because of undesired axial nipple displacement or other irritation.